Postmating Sexual Selection Favors Males That Sire Offspring with Low Fitness
Trine Bilde,1,2,*
Anne Foged,2
Nadia Schilling,2
Göran Arnqvist1
Despite the costs of mating, females of most taxa mate with
multiple males. Polyandrous females are hypothesized to gain
genetic benefits for their offspring, but this assumes paternity
bias favoring male genotypes that enhance offspring viability.
We determined net male genetic effects on female and offspring
fitness in a seed beetle and then tested whether fertilization
success was biased in favor of high-quality male genotypes in
double mating experiments. Contrary to expectations, high-quality
male genotypes consistently had a lower postmating fertilization
success in two independent assays. Our results imply that sexually
antagonistic adaptations have a major and unappreciated influence
on male postmating fertilization success. Such genetic variation
renders indirect genetic benefits an unlikely driver of the
evolution of polyandry.
2 Department of Biological Sciences, University of Aarhus, Ny Munkegade 1540, 8000 Aarhus C, Denmark.
* To whom correspondence should be addressed. E-mail: trine.bilde{at}biology.au.dk
